The Oil Red O staining was used to visualize the
lipid droplets in cancer cells. Cells were washed with
PBS and fixed in 4% paraformaldehyde for 1 h, and
then stained with pre-warmed 0.25% Oil Red O working
solution (0.5% Oil Red O was diluted with propylene
glycol for long-term storage, and working dilutions were
made immediately before use with ddH2O) for 15 minutes
in 60 ºC oven. After being washed twice with PBS, the
cells were photographed under the light microscope
(Nikon Eclipse Ti-S, Japan) at magnification of 200×.